A covered goods wagon or van is a railway goods wagon which is designed for the transportation of moisture-susceptible goods and therefore fully enclosed by sides and a fixed roof. They are often referred to simply as covered wagons, and this is the term used by the International Union of Railways (UIC). Since the introduction of the international classification for goods wagons by the UIC in the 1960s a distinction has been drawn between ordinary and special covered wagons. Other types of wagon, such as refrigerated vans and goods wagons with opening roofs, are closely related to covered wagons from a design point of view. Similar freight cars in North America are called boxcars.